手寫迷你Spring框架

public class DispatcherServlet extends HttpServlet {

     private Map<String,Object> mapping = new HashMap<String, Object>();

     @Override

     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {this.doPost(req,resp);}

     @Override

     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

         try {

             doDispatch(req,resp);

         } catch (Exception e) {

             resp.getWriter().write("500 Exception " + Arrays.toString(e.getStackTrace()));

         }

     }

     private void doDispatch(HttpServletRequest req, HttpServletResponse resp) throws Exception {

         String url = req.getRequestURI();

         String contextPath = req.getContextPath();

         url = url.replace(contextPath, "").replaceAll("/+", "/");

         if(!this.mapping.containsKey(url)){resp.getWriter().write("404 Not Found!!");return;}

         Method method = (Method) this.mapping.get(url);

         Map<String,String[]> params = req.getParameterMap();

         method.invoke(this.mapping.get(method.getDeclaringClass().getName()),new Object[]{req,resp,params.get("name")[0]});

     }

     // 當我暈車的時候，我就不去看原始碼了

     //init 方法肯定幹得的初始化的工作

     //inti 首先我得初始化所有的相關的類， IOC 容器、 servletBean

     @Override

     public void init(ServletConfig config) throws ServletException {

         InputStream is = null;

         try{

             Properties configContext = new Properties();

             is = this.getClass().getClassLoader().getResourceAsStream(config.getInitParameter("contextConfigLocation"));

             configContext.load(is);

             String scanPackage = configContext.getProperty("scanPackage");

             doScanner(scanPackage);

             for (String className : mapping.keySet()) {

                 if(!className.contains(".")){continue;}

                 Class<?> clazz =外匯跟單gendan5.com Class.forName(className);

                 if(clazz.isAnnotationPresent(Controller.class)){

                     mapping.put(className,clazz.newInstance());

                     String baseUrl = "";

                     if (clazz.isAnnotationPresent(RequestMapping.class)) {

                         RequestMapping requestMapping = clazz.getAnnotation(RequestMapping.class);

                         baseUrl = requestMapping.value();

                     }

                     Method[] methods = clazz.getMethods();

                     for (Method method : methods) {

                         if (!method.isAnnotationPresent(RequestMapping.class)) {  continue; }

                         RequestMapping requestMapping = method.getAnnotation(RequestMapping.class);

                         String url = (baseUrl + "/" + requestMapping.value()).replaceAll("/+", "/");

                         mapping.put(url, method);

                         System.out.println("Mapped " + url + "," + method);

                     }

                 }else if(clazz.isAnnotationPresent(Service.class)){

                         Service service = clazz.getAnnotation(Service.class);

                         String beanName = service.value();

                         if("".equals(beanName)){beanName = clazz.getName();}

                         Object instance = clazz.newInstance();

                         mapping.put(beanName,instance);

                         for (Class<?> i : clazz.getInterfaces()) {

                             mapping.put(i.getName(),instance);

                         }

                 }else {continue;}

             }

             for (Object object : mapping.values()) {

                 if(object == null){continue;}

                 Class clazz = object.getClass();

                 if(clazz.isAnnotationPresent(Controller.class)){

                     Field [] fields = clazz.getDeclaredFields();

                     for (Field field : fields) {

                         if(!field.isAnnotationPresent(Autowired.class)){continue; }

                         Autowired autowired = field.getAnnotation(Autowired.class);

                         String beanName = autowired.value();

                         if("".equals(beanName)){beanName = field.getType().getName();}

                         field.setAccessible(true);

                         try {

field.set(mapping.get(clazz.getName()),mapping.get(beanName));

                         } catch (IllegalAccessException e) {

                             e.printStackTrace();

                         }

                     }

                 }

             }

         } catch (Exception e) {

         }finally {

             if(is != null){

                 try {is.close();} catch (IOException e) {

                     e.printStackTrace();

                 }

             }

         }

         System.out.print("MVC Framework is init");

     }

     private void doScanner(String scanPackage) {

         URL url = this.getClass().getClassLoader().getResource("/" + scanPackage.replaceAll("\\.","/"));

         File classDir = new File(url.getFile());

         for (File file : classDir.listFiles()) {

             if(file.isDirectory()){ doScanner(scanPackage + "." +  file.getName());}else {

                 if(!file.getName().endsWith(".class")){continue;}

                 String clazzName = (scanPackage + "." + file.getName().replace(".class",""));

                 mapping.put(clazzName,null);

             }

         }

     }

}